Mahnaz Mohammadi has been denied access to her family or proper legal representation, her lawyer said.

A prominent Iranian documentary film-maker and women's rights activist, whose work includes banned films about Iran's society, has been arrested by unidentified officials.

Mahnaz Mohammadi, 37, was picked up from her home in the capital Tehran by security officers who refused to show a warrant for her arrest and was taken to Evin prison, where many activists are being held.

Speaking by phone from Tehran, her lawyer told the Guardian that Mohammadi had been denied access to her family or proper legal representation and was being kept incommunicado.

News of her arrest comes two weeks after another women's rights campaigner and photojournalist, Maryam Majd, was arrested before departing Tehran as she tried to fly to Germany, where she intended to cover the Fifa Women's World Cup.

Majd, 25, had campaigned for women in Iran to be allowed to enter stadiums to watch football matches. She had been expected to join Petra Landers, a former German national footballer, to work on a book project about women's sport but was detained and transferred to Evin before her departure. She has also been denied access to her lawyer and family.

The arrests of both activists have prompted criticism among human rights groups, which for a long time have condemned Iran for its ongoing crackdown targeting artists and activists. Amnesty International raised serious concerns about both arrests and asked Iran to clarify the reasons behind their detentions.

"We're very concerned about these arrests, and we are following up with their lawyer to ascertain their legal status," Amnesty said.

"The reasons for the arrest of Mahnaz Mohammadi and Maryam Majd have still not been clarified. It appears to be part of an ongoing crackdown on journalists, film-makers, activists and lawyers – anyone whom the authorities fear may challenge their narrow view of what the Islamic Republic of Iran should be."

Amnesty urged Iranian authorities to protect Mohammadi and Majd from torture and give them access to their families and lawyers.

"If they are being held solely for peacefully exercising their right to freedom of expression – as is likely to be the case – then they should be released immediately and unconditionally," Amnesty said.

Maziar Bahari, an Iranian documentary film-maker who was arrested in the aftermath of Iran's 2009 post-election unrest and is the author of the recently published book, Then They Came for Me, said: "The difficulty after such arrests is that you don't know where they have been taken to, what charges they are facing or even which authority has held them in jail."

He added: "Documentary makers are in direct contact with the society and show what's out there, sometimes negative, sometimes positive, but in Iran, where the regime thinks it has the right to intrude in all aspects of the citizens' lives, everything is politicised, and the work of film-makers can be interpreted as a threat to the so-called national security."

Mohammadi, who was also arrested in 2007 and 2009, has directed a handful of films including Women without Shadows (2003), about homeless and deserted women, and The Soul's Children (2004), which was banned.

Among her documentaries, Travelogue (2006) shows a train that departs full of passengers every Thursday from Tehran to Istanbul, and returns home empty. The film discusses issues of immigration, the contradictions of Iran's modern society and homosexuality.

Many film-makers and women's rights campaigners have been arrested and sentenced to long prison terms in Iran in recent years, including the acclaimed director Jafar Panahi, film-maker Mohammad Rasoulof and celebrated lawyer Nasrin Sotoudeh.

Despite the crackdown on the country's film industry, Iran's film-makers have won international recognition. A Separation, a drama by Asghar Farhadi which won the Golden Bear at this year's Berlin film festival, is released on Friday in London cinemas.